Conventionally there has been proposed an up-flow type outdoor unit provided with a fan installed so as to blow air upward and a casing accommodating the fan therein.
For example, in the up-blow type outdoor unit described in Japanese Patent Document 1 (Japanese Unexamined Patent Application No. 2014-129921), the top end of the casing accommodating the fan is configured to be flat and positioned on substantially the same plane.
For this reason, when for example storing a plurality of the outdoor units in a warehouse, it is easy to arrange one or a plurality of the outdoor units on the outdoor unit so as to be vertically stacked, and moreover possible to stabilize the stacked arrangement.
Here, the up-flow type outdoor unit described in Patent Document 1 has a structure in which a large flow passage that is rectangular in plan view, due to being enclosed by side plates, continues on the outlet side of the bellmouth. According to this structure, immediately after passing through the bellmouth, the flow passage area rapidly enlarges.
However, at the portion where the flow passage area is suddenly enlarged, air vortices are generated at the side of the enlarged portion, which could inhibit good airflow and thereby prevent the air volume in the outdoor unit from being sufficiently increased.